Semiconductor device with adjacent non-oxide layers and the fabrication thereof

Abstract

A semiconductor device is disclosed in which a deposited non-oxide layer (44) overlies and physically contacts another non-oxide layer (38) so that no intervening oxide layer is present. The device is fabricated by performing an insitu etch and deposition process. In one embodiment, the device (36) is sealed in a LPCVD chamber (10) and etched using gaseous anhydrous hydrofluoric acid to remove an oxide (40) from one non-oxide layer (38). Then, without exposing the device to a water rinse or to the atmosphere, a chemical vapor deposition process applies the deposited layer (44) upon the other layer (38).

What is claimed is: 
     
       1. A method of depositing a layer upon a surface of a non-oxide body, said depositing occurring substantially without formation of an intervening oxide layer, said method comprising the steps of: enclosing the body in a sealed chamber;   introducing a gaseous etchant into the chamber so that if oxides are present at the body surface, the etchant substantially removes the oxides, while maintaining the temperature of said chamber at grater than 100 degrees Celsius so that water generated by the etching of oxides will vaporize and be driven away from the body surface;   purging the etchant from the chamber;   raising the temperature of the chamber after the step of introducing the gaseous etchant;   after raising the temperature of the chamber, introducing a substance into the chamber which forms the layer upon contact with the body; and   thereafter removing the body from the chamber.   
     
     
       2. A method as claimed in claim 1 wherein: the body surface is silicon; and   said introducing a gaseous etchant step comprises the step of using anhydrous hydrofluoric acid as the etchant.   
     
     
       3. A method as claimed in claim 2 wherein, during said step of introducing a gaseous etchant, the temperature of the chamber is maintained at less than 400° C. to prevent substantial etching of the body surface. 
     
     
       4. A method as claimed in claim 2 wherein said introducing a gaseous etchant step comprises the step of maintaining a chamber pressure of greater than 100 torr to control concentration of the anhydrous hydroflouric acid in the chamber. 
     
     
       5. A method as claimed in claim 4 additionally comprising, simultaneously with said introducing a gaseous etchant step, the step of removing by-products generated by etching oxides within the chamber. 
     
     
       6. A method as claimed in claim 4 wherein said maintaining step comprises the step of maintaining chamber pressure at a pressure of less than one atmosphere. 
     
     
       7. A method as claimed in claim 1 additionally comprising, prior to said introducing a gaseous etchant step, the step of establishing an ultimate pressure in the chamber to remove oxygen from the chamber. 
     
     
       8. A method as claimed in claim 1 additionally comprising, prior to said introducing a gaseous etchant step, the step of flushing the chamber with an inert gas to remove oxygen from the chamber. 
     
     
       9. A method as claimed in claim 8 and additionally comprising, prior to said introducing a gaseous etchant step, the step of establishing an ultimate pressure in the chamber to remove oxygen from the chamber. 
     
     
       10. A method as claimed in claim 1 wherein said step of raising the temperature of the chamber is performed simultaneously with said purging step. 
     
     
       11. A method as claimed in claim 1 additionally comprising the step of completing said purging step prior to said introducing a gaseous substance step. 
     
     
       12. A method of depositing a non-oxide layer upon a surface of a silicon layer without formation of an intervening oxide layer, said method comprising the steps of: enclosing the silicon layer in a chamber;   lowering pressure in the chamber to remove oxygen from the chamber;   introducing a gaseous anhydrous hydrofluoric acid etchant into the chamber so that if oxides are present at the silicon layer surface, the etchant substantially removes the oxides;   maintaining, during said introducing an etchant step, temperature of the chamber at greater than 100° C. and less than 400° C.;   maintaining, during said introducing an etchant step, a chamber pressure of greater than 100 torr to control concentration of the etchant in the chamber;   removing by-products generated by etching oxides;   purging the etchant from the chamber;   raising the temperature of the chamber, after said introducing an etchant step;   introducing a gaseous substance into the chamber which forms the non-oxide layer upon contact with the silicon layer; and   removing the non-oxide and silicon layers from the chamber.